KR20020089828A - Liquid Crystal Display Device and Fabricating Method Thereof and Method of Reworking Polymer using the same - Google Patents

Abstract

PURPOSE: A liquid crystal display device, a method for fabricating the same, and a method for recycling an alignment film by the same are provided to remove an alignment film without any damage of a first protecting film by forming a second protecting film with a selective etching ratio different from the alignment film. CONSTITUTION: A liquid crystal display device includes an organic insulating film as a first protecting film(68) formed on a substrate, an alignment film(74) formed on the organic insulating film, and the SiNx layer as a second protecting film(84) formed on the organic insulating film with different etching conditions from the alignment film, wherein the alignment film is removed by dry type etching by using mixture gas of SF6, O2, O2+Cl2, CF4, etc.

Description

Liquid Crystal Display Device and Manufacturing Method Thereof and Alignment Film Recycling Method Using the Same {Liquid Crystal Display Device and Fabricating Method Thereof and Method of Reworking Polymer using the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, a method for manufacturing the same, and a method for reproducing an alignment film using the same.

In general, a liquid crystal display (LCD) displays an image by adjusting the light transmittance of the liquid crystal using an electric field. To this end, the liquid crystal display device includes a liquid crystal panel in which liquid crystal cells are arranged in a matrix, and a driving circuit for driving the liquid crystal panel. The liquid crystal panel includes pixel electrodes for applying an electric field to each of the liquid crystal cells and a reference electrode, that is, a common electrode. In general, the pixel electrode is formed for each liquid crystal cell on the lower substrate, while the common electrode is integrally formed on the front surface of the upper substrate. Each of the pixel electrodes is connected to a thin film transistor (TFT) used as a switching element. The liquid crystal cell is driven along with the common electrode in accordance with the data signal supplied through the TFT.

Referring to FIG. 1, a liquid crystal display device according to the related art includes a top plate including a black matrix 32, a color filter 30, and a transparent electrode 28 sequentially formed on an upper substrate 11, and a lower substrate 1. The liquid crystal 38 injected into the inner space provided by the lower plate including the thin film transistor and the pixel electrode 22 formed on the upper layer, the spacer 26 formed between the upper plate and the lower plate, and the upper plate and the lower plate and the spacer 26. ). In the upper plate, the black matrix 32 is formed in a matrix form on the upper substrate 11 to divide the surface of the upper substrate 11 into a plurality of cell regions in which the color filters 30 are to be formed, as well as optical interference between adjacent cells. It will act to prevent. On the upper substrate 1 on which the black matrix 32 is formed, color filters 30 of red, green, and blue primary colors are sequentially formed. In this case, each of the three primary color filters 30 absorbs a white light source on the front surface of the upper substrate 1 on which the black matrix 32 is formed and applies a material that transmits only a specific wavelength (red, green, or blue) light. It is formed by post-patterning. On the upper substrate 1 on which the black matrix 32 and the color filter 30 are formed, a transparent electrode 28, which is a transparent conductive film to which a ground potential is supplied, is coated to complete the top plate. A thin film transistor for switching the driving of the liquid crystal cell in the lower plate is formed at the intersection of the gate line 2 and the data line 4 as shown in FIG. 2, and at least one of the data line 2 and the gate line 4. The pixel electrodes 22 overlapping any one are arranged in a matrix and formed on the lower substrate 1. In detail, the gate line 2 and the gate electrode 6 are formed by coating and patterning a metal film on the lower substrate 1 as shown in FIG. 3A. The gate insulating film 12 is formed by entirely depositing on the lower substrate so as to cover the gate line 2 and the gate electrode 6. By sequentially depositing and patterning the first and second semiconductor materials 14 and 16 on the gate insulating layer 12, the active layer 14 and the ohmic contact layer 16 are formed as shown in FIG. 3B. Subsequently, a metal film is coated on the gate insulating film 12 and then patterned to form the data line 4, the source electrode 8, and the drain electrode 10, as shown in FIG. 3C. To form the ohmic contact layer 16 is etched so that the active layer 14 is exposed. The contact hole 20 is formed so that the drain electrode 10 is exposed as shown in FIG. 3D by depositing and patterning the surface of the organic protective film 18 evenly by spin coating the gate insulating film. Next, a transparent conductive material is applied and patterned on the protective layer 18 to form a pixel electrode 22 electrically connected to the drain electrode 10 as shown in FIG. 3E. After the alignment layer 24 is applied to the entire surface of the lower substrate 1 on which the pixel electrode 22 is formed, a rubbing process is performed to complete the lower plate. Finally, the upper and lower plates separately formed as described above are aligned and bonded together. After that, the spherical spacers 26 are dispersed, and then liquid crystal is injected and sealed to complete the liquid crystal display device.

After forming the passivation layer 18 of the liquid crystal display device, if the waiting time for forming the pixel electrode 22 which is the next process becomes long, the passivation layer 18 is left for a long time. The contaminants exposed to the atmosphere are adsorbed on the surface of the protective film 18 thus left. As a result, as a result of testing the lower plate on which the alignment layer 24 is formed, a process of regenerating the alignment layer 24 is performed when a poorly coated alignment layer 36 is generated as shown in FIG. 4. The uncoated alignment film 36 is removed using dry etching to regenerate the alignment film 24. That is, the lower plate coated with the defective alignment layer 36 is mounted in the chamber, and the plasma discharge is caused by injecting O ₂ , O ₂ + Cl ₂ , CF ₄ , SF ₆ gas, or the like into the chamber. Then, a reaction occurs between the injection gas and the poorly coated alignment layer 24, and the alignment layer 24 is etched entirely. However, there is no dry etching ratio between the poorly coated alignment layer 24 and the protective layer 18, and as shown in FIG. 5, the protective layer 18, which is the same organic film series as the poorly coated alignment layer 24, is overetched. (A) appears. For this reason, since the regeneration process of the alignment film 24 cannot be performed, there exists a problem that a yield and productivity fall.

Accordingly, it is an object of the present invention to provide a liquid crystal display device capable of carrying out a regeneration process of an alignment film, a method of manufacturing the same, and a method of reproducing an alignment film using the same.

1 is a cross-sectional view showing a conventional liquid crystal display device.

FIG. 2 is a plan view illustrating a lower substrate of the liquid crystal display shown in FIG. 1.

3A to 3E are cross-sectional views illustrating a method of manufacturing a lower substrate of a liquid crystal display device taken along a line "A-A '" in FIG.

4 is a cross-sectional view illustrating a coating failure of the alignment layer illustrated in FIG. 1.

FIG. 5 is a cross-sectional view illustrating an over-etching phenomenon of the protective film shown in FIG. 4.

6 is a cross-sectional view of a liquid crystal display device according to an embodiment of the present invention.

7A to 7E are cross-sectional views illustrating a method of manufacturing the liquid crystal display device shown in FIG.

FIG. 8 is a cross-sectional view illustrating a coating failure of the alignment layer of the liquid crystal display shown in FIG. 6.

FIG. 9 is a cross-sectional view of a liquid crystal display device in which an alignment film after the defective coating layer shown in FIG. 8 is removed.

FIG. 10 is a cross-sectional view showing an alignment film regeneration process of the liquid crystal display shown in FIG. 9; FIG.

<Description of Symbols for Main Parts of Drawings>

1,51: lower substrate 2,52: gate line

4,54 data line 6,56 gate electrode

8,58 source electrode 10,60 drain electrode

11: upper substrate 12, 62: gate insulating film

14,64: active layer 16,66: ohmic contact gun

18,68,84: protective film 20,70: contact hole

22,72 pixel electrode 24,74 alignment film

26 spacer 28 transparent electrode

30: color filter 32: black matrix

38: liquid crystal

In order to achieve the above object, a liquid crystal display device according to the present invention has an organic insulating film formed on a substrate, an alignment film formed on the organic insulating film, and an etching condition different from that of the alignment film, and is formed on the alignment film and the organic insulating film. And a silicon nitride layer.

The alignment layer may be removed by dry etching during a regeneration process.

The dry etching is characterized in using a mixed gas, such as SF ₆ , O ₂ , O ₂ + Cl ₂ , CF ₄ .

The ratio of the mixed gas is characterized in that SF ₆ : O ₂ = 1:50 or more.

The ratio of the mixed gas is characterized in that SF ₆ : O ₂ = 1:70 or more.

The high frequency power (RF power) used during the etching is characterized in that about 500 ~ 1500W.

The thin film transistor formed under the organic passivation layer may include a gate electrode and a gate line formed on the substrate, a gate insulating film formed on the substrate, a semiconductor layer formed on the gate insulating film to correspond to the gate electrode; Source and drain electrodes are formed on the gate insulating layer with a channel having a predetermined size therebetween.

A pixel electrode is further provided to be in electrical contact with the drain electrode, and the pixel electrode is formed to overlap at least one of the data line and the gate line.

In order to achieve the above object, a method of manufacturing a liquid crystal display device according to the present invention comprises the steps of forming an organic insulating film on the substrate, forming an alignment film on the organic insulating film, and having an etching condition different from the alignment film Forming a silicon nitride layer on the alignment layer and the organic insulating layer.

The alignment layer may be removed by dry etching during a regeneration process.

The dry etching is characterized in using a mixed gas, such as SF ₆ , O ₂ , O ₂ + Cl ₂ , CF ₄ .

The ratio of the mixed gas is characterized in that SF ₆ : O ₂ = 1:50 or more.

The ratio of the mixed gas is characterized in that SF ₆ : O ₂ = 1:70 or more.

The high frequency power (RF power) used during the etching is characterized in that about 500 ~ 1500W.

A method of manufacturing a thin film transistor formed under the organic insulating film includes forming a gate electrode and a gate line on the substrate, forming a gate insulating film on the substrate to cover the gate electrode and the gate line; Forming a data line, a source electrode and a drain electrode on the gate insulating layer.

The method may further include forming a pixel electrode in electrical contact with the drain electrode, wherein the pixel electrode is formed to overlap at least one of the data line and the gate line.

According to an aspect of the present invention, there is provided a method of reproducing a liquid crystal display device, wherein the organic protective layer and the silicon nitride layer are sequentially formed on a substrate to detect a defective alignment layer formed on the silicon nitride layer. And removing the defective alignment layer under different etching conditions from the silicon nitride layer, and regenerating a normal alignment layer on the silicon nitride layer.

The defective alignment layer is characterized in that it is removed by dry etching during the regeneration process.

The dry etching is characterized in using a mixed gas, such as SF ₆ , O ₂ , O ₂ + Cl ₂ , CF ₄ .

The ratio of the mixed gas is characterized in that SF ₆ : O ₂ = 1:50 or more.

The ratio of the mixed gas is characterized in that SF ₆ : O ₂ = 1:70 or more.

The high frequency power (RF power) used during the etching is characterized in that about 500 ~ 1500W.

Other objects and features of the present invention in addition to the above objects will become apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 6 to 10.

Referring to FIG. 6, the lower substrate 51 of the liquid crystal display according to the present invention is connected to a TFT positioned at an intersection of the data line 54 and the gate line 52 and the drain electrode 60 of the TFT. The pixel electrode 72 and the alignment film 74 coated to cover the pixel electrode 72 are provided.

The TFT is connected to the pixel electrode 72 through the gate electrode 56 protruding from the gate line 52, the source electrode 58 protruding from the data line 54, and the contact hole 70. It is provided. Further, the TFT is formed by the gate insulating film 62 for insulating the gate electrode 56 and the source and drain electrodes 58 and 60, and the gate electrode 56 and the drain electrode by the gate voltage supplied to the gate electrode 56. The semiconductor layers 64 and 66 are further provided for forming the conduction channel between 60. Such TFT selectively supplies the data signal from the data line 54 to the pixel electrode 72 in response to the gate signal from the gate line 52.

The pixel electrode 72 is formed in a cell region divided by the data line 54 and the gate line 52 and is made of a transparent conductive material having high light transmittance. The pixel electrode 72 is formed on the first and second passivation layers 68 and 84 applied to the entire lower substrate 51. The first passivation layer 68 is formed of an organic insulating material, and the second passivation layer 84 is formed of silicon nitride (SiNx), which is an inorganic insulating material. It is electrically connected to the drain electrode 60 through the contact holes 70 formed in the first and second passivation films 68 and 84. The pixel electrode 72 generates a potential difference from a common transparent electrode (not shown) formed on the upper substrate by a data signal supplied through the TFT. This potential difference causes the liquid crystal located between the lower substrate 51 and the upper substrate to rotate by dielectric anisotropy. The liquid crystal transmits light incident from the light source via the pixel electrode 72 toward the upper substrate.

The alignment layer 74 is formed on the second passivation layer 84 in the process of determining the initial molecular arrangement of the liquid crystal molecules. This alignment film 74 is formed by applying polyimide with a roller. The alignment layer 74 has an etching condition different from that of the second passivation layer 84, and when the alignment layer 74 is poorly coated, the alignment layer 74 is removed without losing the first passivation layer 68. Then, the regeneration process of the alignment film 74 is performed.

7A to 7E are cross-sectional views sequentially illustrating a method of manufacturing the liquid crystal display device illustrated in FIG. 6.

Referring to FIG. 7A, a gate line 52 and a gate electrode 56 are formed on the substrate 51.

The gate line 52 and the gate electrode 56 are formed by depositing aluminum (Al), copper (Cu), or the like by a deposition method such as sputtering and then patterning.

Referring to FIG. 7B, an active layer 64 and an ohmic contact layer 66 are formed on the gate insulating layer 62.

The gate insulating layer 62 is formed by depositing an insulating material on the entire surface of the gate line 52 and the gate electrode 56 by using a plasma enhanced chemical vapor deposition (PECVD) method. The active layer 64 and the ohmic contact layer 66 are formed by stacking and patterning the first and second semiconductor layers on the gate insulating film 62.

The gate insulating layer 62 is made of an insulating material such as silicon nitride (SiNx) or silicon oxide (SiOx). The active layer 64 is formed of amorphous silicon that is not doped with impurities, which is the first semiconductor layer. In addition, the ohmic contact layer 66 is formed of amorphous silicon doped with an N-type or P-type impurity at a high concentration, which is a second semiconductor layer.

Referring to FIG. 7C, a data line 54, a source electrode 58, and a drain electrode 60 are formed on the gate insulating layer 62.

The data line 54, the source electrode 58, and the drain electrode 60 are formed by depositing and patterning a metal layer on the entire surface by a CVD method or a sputtering method. After the source electrode and the drain electrode 60 are patterned, the ohmic contact layer 46 corresponding to the gate electrode 56 is also patterned to expose the active layer 44. The portion of the active layer 44 corresponding to the gate electrode 56 between the source and drain electrodes 58 and 60 becomes a channel.

The data line 54, the source electrode 58, and the drain electrode 60 are formed of chromium (Cr) or molybdenum (Mo).

Referring to FIG. 7D, first and second passivation layers 68 and 84 are formed on the gate insulating layer 62.

The first and second protective layers 68 and 84 sequentially deposit the first and second insulating materials on the gate insulating layer 9 to cover the data line 54, the source electrode 58, and the drain electrode 60. It is formed by patterning after evaporation. A contact hole 70 is formed through the first and second passivation layers 68 and 84 to partially expose the surface of the drain electrode 60.

The first passivation layer 68 is formed of an organic insulator having a low dielectric constant such as an acryl organic compound, Teflon, benzocyclobutene (BCB), cytope, or perfluorocyclobutane (PFCB).

The second protective layer 84 is formed of silicon nitride (SiNx), which is an inorganic insulator having an etching ratio different from that of the alignment layer 74 formed later. Among these, preferably, silicon nitride (SiNx) contains a large amount of hydrogen (H-) groups. In detail, silicon nitride (SiNx) is less seriously polluted, causing insufficient adhesion to the alignment layer 74 on the surface even when exposed to the air for a long time, and the hydrogen group (H−) contained in silicon nitride (SiNx) is the first The protective layer 68 and the adhesive strength is enhanced to improve the characteristics of the device.

Referring to FIG. 7E, a pixel electrode 72 is formed on the second passivation layer 84.

The pixel electrode 72 is formed by depositing a transparent conductive material on the second protective layer 84 and patterning the same.

The pixel electrode 72 is in electrical contact with the drain electrode 60 through the contact hole 70.

The pixel electrode 72 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), or indium tin zinc oxide (INO). Oxide: ITZO).

The alignment layer 74 is applied to the entire surface of the lower substrate 51 thus formed, and then a rubbing process is performed to complete the lower plate.

As a result of testing the lower plate on which the alignment layer 74 is formed, as shown in FIG. 8, when a poorly coated alignment layer 86 is found, a process of regenerating the alignment layer 74 is performed. The defective alignment film 86 is removed using dry etching. The lower plate on which the bad alignment film 86 is applied is mounted in the chamber, and SF ₆ , O ₂ , O ₂ + Cl ₂ , CF ₄ gas, etc. are injected into the chamber, and SF ₆ : O ₂ = 1:50 or more, The most ideal case is SF ₆ : O ₂ = 1:70 or more. And, the high frequency power (RF Power) causes a plasma discharge when about 500 to 1500W. Then, as the reaction occurs between the injection gas and the poor alignment layer 86, the defective alignment layer 86 is etched and removed entirely without loss of the first passivation layer 68 as shown in FIG. After the defective alignment film 86 is removed, the substrate is conveyed again in the forming process of the alignment film 74, so that the regeneration process of the alignment film 74 is possible as shown in FIG.

As described above, the liquid crystal display device according to the present invention, a method of manufacturing the same, and a method of reproducing an alignment film using the same according to the present invention form a second protective layer having a selective etching ratio different from that of the alignment film so that the poorly coated alignment film is not lost. It can remove, and the regeneration process of an oriented film can be performed. This can improve productivity and yield.

In addition, the liquid crystal display device according to the present invention, a method of manufacturing the same, and a method for reproducing an alignment film using the same according to the present invention form a second protective layer with a gas containing hydrogen group (H-), thereby protecting the first by the hydrogen group (H-). Adhesion with the layer can be enhanced.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (22)

An organic insulating film formed on the substrate, An alignment film formed on the organic insulating film; And a silicon nitride layer having an etching condition different from that of the alignment layer and formed on the alignment layer and the organic insulating layer. The method of claim 1, And the alignment layer is removed by dry etching during a regeneration process. The method of claim 2, The dry etching is a liquid crystal display device using a mixed gas such as SF ₆ , O ₂ , O ₂ + Cl ₂ , CF ₄ . The method of claim 3, wherein The ratio of the mixed gas is SF ₆ : O ₂ = 1:50 or more liquid crystal display device. The method of claim 3, wherein The ratio of the mixed gas is SF ₆ : O ₂ = 1:70 or more characterized in that the liquid crystal display device. The method of claim 5, The high frequency power (RF power) used during the etching is characterized in that about 500 ~ 1500W. The method of claim 1, The thin film transistor formed under the organic protective layer A gate electrode and a gate line formed on the substrate; A gate insulating film formed on the substrate; A semiconductor layer formed on the gate insulating layer to correspond to the gate electrode; And a source and a drain electrode formed on the gate insulating film with a channel having a predetermined size therebetween. The method of claim 7, wherein Further comprising a pixel electrode to be in electrical contact with the drain electrode, And the pixel electrode is formed to overlap at least one of the data line and the gate line. Forming an organic insulating film on the substrate; Forming an alignment layer on the organic insulating layer; And forming a silicon nitride layer on the alignment layer and the organic insulating layer having an etching condition different from that of the alignment layer. The method of claim 9, Wherein the alignment layer is removed by dry etching during a regeneration process. The method of claim 10, The dry etching is a manufacturing method of a liquid crystal display device, characterized in that using a mixed gas, such as SF ₆ , O ₂ , O ₂ + Cl ₂ , CF ₄ . The method of claim 11, The ratio of the mixed gas is SF ₆ : O ₂ = 1:50 or more manufacturing method of the liquid crystal display device. The method of claim 11, The ratio of the mixed gas is SF ₆ : O ₂ = 1:70 or more method for manufacturing a liquid crystal display device. The method of claim 11, The high frequency power (RF power) used during the etching is about 500 ~ 1500W manufacturing method of the liquid crystal display device. The method of claim 9, A method of manufacturing a thin film transistor formed under the organic insulating film Forming a gate electrode and a gate line on the substrate; Forming a gate insulating film on the substrate to cover the gate electrode and the gate line; And forming a data line, a source electrode, and a drain electrode on the gate insulating film. The method of claim 15, Forming a pixel electrode in electrical contact with the drain electrode; The pixel electrode is formed to overlap at least one of the data line and the gate line. Forming an organic passivation layer and a silicon nitride layer on the substrate sequentially to detect a defective alignment layer formed on the silicon nitride layer; Removing the defective alignment layer under different etching conditions between the defective alignment layer and the silicon nitride layer; And regenerating a normal alignment layer on the silicon nitride layer. The method of claim 17, And the defective alignment layer is removed by dry etching during the regeneration process. The method of claim 18, The dry etching is a method for reproducing a liquid crystal display device, characterized in that a mixed gas such as SF ₆ , O ₂ , O ₂ + Cl ₂ , CF _4, or the like is used. The method of claim 19, The ratio of the mixed gas is SF ₆ : O ₂ = 1:50 or more regeneration method of the liquid crystal display device. The method of claim 19, The ratio of the mixed gas is SF ₆ : O ₂ = 1:70 or more regeneration method of a liquid crystal display device. The method of claim 19, The high frequency power (RF power) used during the etching is about 500 ~ 1500W of the reproduction method of the liquid crystal display device.